Global and European regional assessment: Endangered (EN)
EU 27 regional assessment: Endangered (EN)

This species is endemic to Croatia and Bosnia and Herzegovina in the western Balkans. The Dalmation Barbel-Gudgeon has a restricted range, with an area of occupancy (AOO) of c.400 km², which meets the threshold for the Endangered category under Criterion B2 (AOO < 500 km²). It occurs at five locations where the extent and quality of habitat are estimated to be declining.

Therefore, this species is assessed as Endangered under Criterion B (B1ab(iii)), both globally and for the EU 27 member states.

This species is endemic to the Dinaric Karst region in the western Balkans. It occurs in the Krka and Cetina river systems in Dalmatian Zagora, Croatia, and in the isolated Livanjsko, Glamočko and Duvanjsko poljes in Bosnia and Herzegovina, which are naturally connected to the Cetina via subsurface karstic conduits. There are no reports from the upper Krka River or its tributaries upstream of the Bilušića Buk waterfall, but it is present in the Čikola tributary system in the lower part of the catchment.

Records from the Zrmanja River drainage in Croatia represent cases of misidentification, while it has reportedly been introduced to lakes Blidinje and Šatorsko, plus the Lištica River (Neretva River catchment) in Bosnia and Herzegovina.

This species' current population size and trend have not been quantified, and the number of subpopulations is unclear. It has declined markedly in some parts of its range, e.g., Livanjsko polje, since the turn of the 21^st century, but remains abundant in others, e.g., the Čikola River (Krka River system).

This species naturally inhabits spring-fed karstic river systems, lakes and associated temporal wetlands characterised by complex surface-groundwater hydrological interactions and seasonal fluctuations in discharge.

In Bosnia and Herzegovina, it is restricted to a series of isolated karstic poljes. Each of these comprises a depressed flat plain enclosed by limestone ridges, around the borders of which rise intermittent sinking rivers and springs which flow above ground for short distances before submerging into ponors. Much of this water subsequently resurfaces in adjacent poljes or the headwaters of larger rivers. Under natural conditions, part of each polje would be inundated to form a temporal wetland between early winter and early summer each year, but this no longer occurs throughout much of the Dalmatian Barbel-Gudgeon's range (see 'Threats').

Like a number of other fish species that are endemic to the Dinaric Karst region, this species utilises estavelles and ponors to enter subsurface waterbodies. This behaviour largely occurs during periods of drought or cold winters, and many individuals are understood to spend considerable periods of time underground.

It has successfully colonised some artificial waterbodies, most notably the Buško Blato accumulation lake, Ždralovački Canal and a few disused lignite mining pits which have filled with water in Livanjsko polje (but see 'Threats').

It is sexually dimorphic, with females growing to a larger size than males.

Reproduction typically takes place in temporal wetlands. Spawning continues for a month or more when temperatures reaches 13-17°C, usually from April to June, with females using a modified urogenital papilla to deposit eggs in crevices between rocks and roots of aquatic plants.

This species is a generalised omnivore and feeds on periphyton, benthic algae, plankton and aquatic invertebrates. It is believed to forage mostly at night.

This species is threatened by diffuse and point-source agricultural and domestic pollution, eutrophication, construction of dams and weirs, canalisation of river channels, water abstraction and other forms of habitat modification. All poljes within its range have been modified to reduce the extent of annual flooding and provide reclaimed land for agriculture, which has altered hydrological regimes and significantly reduced the extent of spawning and nursery habitat for native fish species while encouraging the establishment of introduced taxa (see below).

In particular, the Buško Blato accumulation lake was constructed during the 1970s in order to provide water for hydropower generation and agriculture, and has largely eliminated natural flooding processes in Livanjsko and Duvanjsko poljes. Water from Buško Blato and springs rising in other parts of Livanjsko polje is directed through a canal system to the smaller Lipsko compensation lake, which regulates discharge towards a hydroelectric power plant located at the source of the Ruda River, a major tributary of the Cetina.

Elsewhere, the Cetina River has been further modified for water storage and generation of hydroelectricity, with a series of power plants, dams, accumulation lakes, tunnels and pipelines constructed within the system. These engineering works have resulted in an overall reduction in discharge and interfered with sedimentation rates as well as the hydrological regime of some left-bank tributary springs. A number of springs have also been tapped for domestic water supply, thus further reducing their output. Some stretches of the main stem and springs have been channelised leading to a loss in habitat heterogeneity. The middle reaches of the Cetina pass through Sinjsko polje, which has mostly been reclaimed for agriculture. The river is polluted downstream of the polje, where it receives diffuse agricultural contaminants plus point-source domestic and industrial pollution from the towns of Sinj and Trilj.

While most of the Krka River system is relatively well-preserved, the source spring of the Čikola River is exploited for drinking water, and its floodplain is intensively-cultivated east of the town of Drniš, where water abstraction via a network of ditches, sluice gates, small weirs, tunnels, pipelines and groundwater extraction sites has decreased the output of some tributaries and significantly reduced the extent of ephemeral wetlands. Moreover, diffuse and point-source agricultural and domestic pollution is understood to be contaminating the river downstream of this area.

Non-native fish species established within the Dalmatian Barbel-Gudgeon's range include Eurasian Pikeperch (Sander lucioperca), Pumpkinseed (Lepomis gibbosus), Common Carp (Cyprinus domestic strain), Prussian Carp (Carassius gibelio), Eurasian Tench (Tinca tinca), Topmouth Gudgeon (Pseudorasbora parva), Wels Catfish (Silurus glanis) and Rainbow Trout (Oncorhynchus mykiss), all of which are known to exert negative effects on native taxa through hybridisation, predation, pathogen transmission or resource competition. The presence of these and other taxa is believed to be the primary driver of decline in Buško Blato, although a pollution event that occurred in 2011 has also been implicated.

Low effective subpopulation size and loss of genetic diversity, potentially leading to site-scale extirpations, has also been identified as a plausible threat throughout its range should the current declines in abundance continue.

This species continues to be fished commercially in Bosnia and Herzegovina and is targeted by poachers in Croatia.

This species is considered to be a local delicacy and is fished commercially at a small scale. This practice is illegal in Croatia.

This species is included in Annex II of the European Union Habitats Directive. It is currently assessed as Endangered for the National Red Lists of both Croatia and Bosnia and Herzegovina.

It is nationally protected in Croatia, where it is covered by the Nature Protection Act (OG 80/13) and Ordinance on Strictly Protected Taxa (OG 144/13, 73/16), and regionally-protected in the Federation of Bosnia and Herzegovina. Part of its range overlaps with the boundaries of Krka National Park in Croatia, and it also occurs in several protected areas which are included in the European Union's Natura 2000 network. Livanjsko polje is listed in The Ramsar Convention on Wetlands of International Importance (site no. 1786).

A deeper understanding of its present distribution, population status (size and trend), life history and response to ongoing threats would likely prove beneficial in the design of any structured management plan.